Friday Video and Image of the Day--Molting

Flickr Uploaded on June 8, 2006 by Graham Racher

These African Penguin chicks are experiencing their first molt.



Penguin Feathers

1. Shiny feathers uniformly overlap to cover a penguin's skin (del Hoyo, et al., 1992). Feathers are highly specialized-short, broad, and closely spaced, helping to keep water away from the skin. Tufts of down on the feather shafts contribute to the insulative properties of the feathers.

2. Penguins have more feathers than most other birds, with about 70 feathers per square inch.

3. Most penguin species go through one complete molt (shed their feathers) each year, usually after the breeding season. The exception is the Galapagos penguin, which usually goes through two molts annually (del Hoyo, et al., 1992).

a. Molting is an essential function, as feathers wear out during the year. Feathers become worn when penguins rub against each other, come in contact with the ground and water, and regularly preen (clean, rearrange, and oil) their feathers (Sparks and Soper, 1987).

b. The new feather grows under the old one, pushing it out. The old feather does not fall out until the new one is completely in place. The molt is patchy and can give individual penguins a scruffy look (del Hoyo, et al., 1992).

c. During the molt, feathers lose some of their insulating and waterproofing capabilities, and penguins stay out of the water until their plumage is restored to optimum condition (del Hoyo, et al., 1992; Sparks and Soper, 1987).

d. Depending on the species, the average length of the molt varies from 13 days for the Galapagos penguin to 34 for the emperor penguin (del Hoyo, et al., 1992).

e. Because penguins don't enter the water to feed during a molt, they fast. Before their molt, they build a fat layer, which provides energy until the molt is over (del Hoyo, et al., 1992).

Information courtesy of Seaworld @
http://www.seaworld.org/infobooks/Penguins/physical.html